A group of 58 Labour backbenchers, including nine former government ministers, published an alternative white paper yesterday challenging the government's proposals to establish independent state secondary schools. The MPs said the plans were likely to "strengthen rather than break" the link between being poor and underachieving in education.

Tony Blair stood by his reforms in the Commons, telling MPs they were "the right changes to make", and government sources said the rebels had underestimated the degree to which local councils would still be able to coordinate local school provision. But privately ministers predict the government will have to make concessions if its plans are to get through parliament.

The rebel MPs, launching a website and a campaign reaching out to 10,000 party members, said they were not trying to destroy Mr Blair's leadership but rather to protect the education of disadvantaged children. They did not enlist the support of MPs seen as serial rebels - although doing so would easily have given them 100 backbench signatories.

Those backing the alternative white paper include Nick Raynsford, a former local government minister, John Denham, a former Home Office minister, Angela Eagle, another former Home Office minister, Lady Morris, a former education secretary, and Alan Whitehead, a former local government minister. Many would describe themselves as firm New Labour supporters.

Mr Denham said: "The reforms, put together, could be counterproductive and worsening the position of the most disadvantaged pupils." He called for a fuller explanation of government plans for trusts schools, including what would happen if they failed.

Lady Morris said: "A further move to independent state schools will actually stop schools making the essential links to help other schools and teach each other. The white paper should have been stressing interdependence."

Mr Raynsford said local councils would find it difficult to coordinate local education as they would be forced into competing for the most able pupils.

According to the alternative white paper, "if every school becomes its own admissions authority, it will become extremely difficult, if not impossible, for local authorities to coordinate the admissions process, ensure all admissions authorities comply with the codes of practice, ensure that all children are allocated a place in a local school and predict and prepare for future requirements for school places. It is most unlikely that any school will, under this arrangement, voluntarily amend its admissions policy to include more difficult children."

Challenged in the Commons by David Cameron to say whether he would accept the rebel amendments, Mr Blair replied: "We will stick with the changes in the white paper because they are the right changes to make." But privately the tone is more conciliatory.

In the first sign of flexibility, the government withdrew a planned revised code of admissions saying it needed more time to consult. Ministers are under pressure to make the code binding on schools and placed in statute. The government says the code is already enforced by a statutory official, but may offer a compromise.

Number 10 believes the differences between the rebels and its own plans can be bridged before the publication of the bill in February. Some of the differences are based on a misreading of the white paper, or misinterpretation of current education law, they claim. Number 10 will spend the next two months trying to disentangle those with genuine concerns from those with a private agenda to use the bill to hasten Mr Blair's retirement.

With the Conservatives and rightwing press determined to show Mr Blair's authority is waning, Number 10 will be reluctant to be seen to be climbing down.